Glossary

Ancillary services

Ancillary services are all actions of grid users that help grid operator to maintain the balance on the transmission grid. Most important ancillary services are reserve products (R1, R2, R3, R3DP etc), voltage regulation and black-start capability.

API

Application Programming Interface

Cairn

Cairn is the new name of PERSEE (oPtimizER for System Energy managEment)

CAPEX

CAPital EXpenditure or CAP EXpense is the money an organization or corporate entity spends to buy, maintain, or improve its fixed assets, such as equipment, vehicle and so on.

COP

The coefficient of performance or COP (sometimes CP or CoP) of a heat pump, refrigerator or air conditioning system is a ratio of useful heating or cooling provided to work (energy) required.

Higher COPs equate to higher efficiency, lower energy (power) consumption and thus lower operating costs. The COP is used in thermodynamics. The COP usually exceeds 1, especially in heat pumps, because instead of just converting work to heat (which, if 100% efficient, would be a COP of 1), it pumps additional heat from a heat source to where the heat is required.

The COP is highly dependent on operating conditions, especially absolute temperature and relative temperature between sink and system, and is often graphed or averaged against expected conditions.

CPLEX

The CPLEX Optimizer was named for the simplex method implemented in the C programming language. The IBM ILOG CPLEX Optimizer solves integer programming problems, very large linear programming problems using either primal or dual variants of the simplex method or the barrier interior point method, convex and non-convex quadratic programming problems, and convex quadratically constrained problems (solved via second-order cone programming, or SOCP)

CSV

Comma-separated values (CSV) is a text file format that uses commas to separate values, and newlines to separate records. A CSV file stores tabular data (numbers and text) in plain text, where each line of the file typically represents one data record. Each record consists of the same number of fields, and these are separated by commas in the CSV file. If the field delimiter itself may appear within a field, fields can be surrounded with quotation marks. The CSV file format is one type of delimiter-separated file format. Delimiters frequently used include the comma, tab, space, and semicolon. Delimiter-separated files are often given a “.csv” extension even when the field separator is not a comma. Many applications or libraries that consume or produce CSV files have options to specify an alternative delimiter.

FMI

Functional Mock-up Interface is an open standard for exchanging dynamical simulation models between different tools in a standardized format.

FMU

Functional Mock-up Unit

A file (with extension.fmu) that contains a simulation model that adheres to the FMI standard.

GAMS

General Algebraic Modeling System

GAMS is a high level modeling system for mathematical programming and optimization. It consists of a language compiler and a range of associated solvers. The GAMS modeling language allows modelers to quickly translate real world optimization problems into computer code. The gams language compiler then translates this code into a format the solvers can understand and solve. This architecture provides great flexibility, by allowing changing the solvers used without changing the model formulation. https://gams.com/

GUI

Graphic User Interface

HMI

Human Machine Interface

IRR

Internal Rate of Return is the rate for which the cash flows pay back the investment (NPV=0).

JSON

JavaScript Object Notation (JSON) is a standard text-based format for representing structured data based on JavaScript object syntax. It is commonly used for transmitting data in web applications (e.g., sending some data from the server to the client, so it can be displayed on a web page, or vice versa).

LCA

Life Cycle Assessment

LCOE

Levelized Cost of Energy is the cost for which energy must be sold to cancel the NPV (NPV=0).

LHV

Lower Heating Value

MILP

Mixed Integer Linear Problem

MODELICA

Modelica is an object oriented language to model cyber-physical systems. It supports acausal connection of reusable components governed by mathematical equations to facilitate modeling from first principles.

NPV

Net Present Value is the sum of the levelized cash flows. NPV > 0 means that the project is profitable (incomes cover the expenses, the investment can be paid back, an excess profit is created).

OPEX

An OPerating EXpense is an ongoing cost for running a equipement or system. In Cairn, it represents the maintenance of the component.

PEGASE

PEGASE is a co-simulation platform developped by CEA, based on FBSF layer developped by L3S (open source since 2021: https://github.com/L-3S/SiFFra).

Python

Python is a high-level, general-purpose programming language. Its design philosophy emphasizes code readability with the use of significant indentation. Python is dynamically typed and garbage-collected. It supports multiple programming paradigms, including structured (particularly procedural), object-oriented and functional programming. It is often described as a “batteries included” language due to its comprehensive standard library.

TURPE

The financial resources required for system operators to carry out their public service missions are obtained mainly through the public transmission system access tariff (TURPE, Tarifs d’Utilisation des Réseaux Publics d’Electricité).

UDI

User Defined Indicator